Helical bar concave

ABSTRACT

A method of manufacturing a helical bar concave from a flat, rolled laser cut arrangement that provides a net helical concave functionality. Laser cutting a flat metal sheet to form helical cutouts defining a percent open area having a helical geometry in combination with configurable rub bars mounted in a helical fashion results in a configurable helical bar concave in which the number or aggressiveness of the threshing surface on the inside radius of the grate may be changed and/or the rub bars may be moved to the outside of the grate to change the percent open area and hence the separation characteristics of the concave.

TECHNOLOGY FIELD

The present invention relates generally to agricultural harvesters, andmore particularly, to a helical bar concave for use with an axial flowharvester having a threshing and separating unit with a rotor foradvancing crop material along a generally helical path.

BACKGROUND

A combine harvester is a machine that is used to harvest grain crops.The objective is to complete several processes, which traditionally weredistinct, in one pass of the machine over a particular part of thefield. Among the crops that may be harvested with a combine are wheat,oats, rye, barley, corn, soybeans, and flax or linseed. The waste (e.g.,straw) left behind on the field includes the remaining dried stems andleaves of the crop having limited nutrients which may be, for example,chopped and spread on the field or baled for feed and bedding forlivestock.

The cut crop may be picked up and fed into the threshing and separatingmechanism of the combine, typically consisting of a rotating threshingdrum to which grooved steel bars may be bolted. These bars thresh orseparate the grains and chaff from the straw through the action of thedrum against the concaves, i.e., shaped “half drum,” that may also befitted with steel bars and a meshed grill, through which grain, chaffand smaller debris may fall, whereas the straw, being too big or long,is carried through to the outlet. Typically, the drum speed may bevariably adjustable and the distance between the drum and concave may befinely adjustable laterally and together, to achieve optimum separationand output.

In an axial flow combine, the harvested crop is threshed and separatedas it is conveyed between a longitudinally arranged rotor and the innersurface of an associated chamber comprising threshing and separatingconcaves. The crop material spirals and is conveyed along a helical pathalong the inner surface of the chamber until it reaches the end thereoffor expulsion out of the rear of the combine. In other embodiments, thecombine may include a threshing design that is positioned transverselyin a combine

Even though the crop flow spirals and follows a helical path as the cropis pulled through the rotor, historically and up until somewhatrecently, all of the rub bars of the concave were straight andperpendicular with the side sheet (side walls) of the weldment of theconcave frame. More recently, concaves have incorporated angled cross orrub bars so that the bars are more perpendicular to the crop flow toincrease the likely expulsion of grain through the concave, and toincrease the aggressiveness of the concave on the crop. These angle rubbars extend fully across the width of the concave.

Conventional concaves are of a welded construction. For example, atypical welded construction of a concave may include welded rub barsthat may form a helical shape relative to the parallel side bars (wires)and frame side walls and are of various lengths depending on theirposition on the concave. The rub bars extend fully from a side or edgeof the concave to another side or edge. As such, these conventionalwelded concaves have multiple part numbers involved and there is adetailed and intricate weld fixturing required to physically positionthese bars appropriately in a helical fashion. Conventional weldedconstruction used to produce the helical shape is very time and costintensive.

As can be appreciated by one of ordinary skill in the art, there is atremendous amount of weld joints on each part and the weld processintroduces heat and distortion on the concave. The concave is somewhatof a precision part typically requiring manufacturing and installationprecision within millimeters of the radius, i.e. an internal radius ofthese parts. Welding may end up distorting the part and causing the partto be out of desired manufacturing tolerances.

What is needed is an improved helical bar concave and method of making ahelical bar concave that solve one or more of the above problems withconventional concaves.

SUMMARY

Embodiments of the present invention address and overcome one or more ofthe above shortcomings and drawbacks, by providing a helical bar concaveand a low cost and easy method of manufacturing a helical bar concave.This technology is particularly well-suited for, but by no means limitedto, use with an axial flow harvester having a threshing and separatingunit with a longitudinally arranged rotor for advancing crop materialalong a generally helical path.

Embodiments of the present invention are directed to a helical barconcave including a frame having two side walls and two end wallsconnected together to define a top opening. A radius is provided in atop edge of the side walls. A grate is connected to the top edges of theside walls and end walls, and over the top opening of the frame. Thegrate having an inside radius conforming to the radius of the top edgesof the side walls. The grate includes a functional surface on itsinterior surface for contacting a crop. A plurality of helical cutoutsin the grate defining a percent open area having a helical geometry. Thegrate includes helical mounting framework separating the cutouts. Thehelical geometry of the helical cutouts and helical mounting frameworkis generally in the same direction, and parallel to a flow path of aspiraling crop flow when, for example, the helical bar concave ismounted in a threshing and separation system of a combine. A pluralityof rub bars are mounted to a surface of the grate and connected to themounting framework. The rub bars are mounted to the grate in a helicalfashion —meaning the rub bars are mounted such that a length of each ofthe rub bars is substantially perpendicular to the helical cutouts andhelical mounting framework.

According to one aspect of the invention, the rub bars compriseconfigurable rub bars that may be mounted to one or both of: theinterior surface to create a rub surface; and/or an exterior surface ofthe grate to cover-up one or more cutouts and reduce the percent openarea of the grate.

According to another aspect of the invention, holes are formed (e.g.,cut or drilled) in the mounting frames and corresponding holes areformed (e.g., cut or drilled) in the rub bars. Fasteners may extendthrough the holes in the mounting frames and the holes in the rub barsto connect the rub bars to the grate. In some embodiments, the fastenerscomprise bolts and nuts.

According to one aspect of the invention, the rub bars comprisesegmented rub bars. The segmented rub bars including a straight piecehaving a length that does not span the width of the concave allowing thesegmented straight rub bar to be mounted to a substantiallycircumferential helical surface of the grate in a helical fashionwithout bending or twisting of the rub bar or grate. In someembodiments, the segmented rub bars may span only span two mountingframes. In some embodiments, the segmented rub bars only span threemounting frames.

In another aspect of the invention, the rub bars comprise U-shaped rubbars having a rectangular shaped channel having two side edges and twoends, and two upset edges extending at an angle from the side edges ofthe channel. In another embodiment, the rub bars comprise L-shaped rubbars. In another embodiment, the rub bars comprise rectangular shapedrub bars. In another embodiment, the rub bars comprise fingers extendingupward from the rub bar.

According to another embodiment of the invention, the improved helicalbar concave is used with an agricultural combine. The agriculturalcombine includes an axially arranged threshing and separation system. Athreshing chamber extends axially within the threshing and separationsystem. A cylindrical threshing rotor is supported and rotatable in apredetermined direction about a rotational axis in the threshing andseparation system for conveying a flow of crop material in a helicalflow path through the threshing chamber extending circumferentiallyaround the rotor. Helical bar concaves extend circumferentially around aportion of the rotor in a spaced apart relationship to allow the flow ofcrop to pass in the space between the spinning rotor and the concaves.The helical bar concaves include a frame having walls defining a topopening. A grate is connected over the top opening of the frame, thegrate having an inside radius that substantially conforms to thecurvature of the rotor. A functional surface is provided on the interiorsurface of the grate for contacting a crop. Helical cutouts in the gratedefine a percent open area having a helical geometry. Helical mountingframes in the grate separate the cutouts. When the helical bar concaveis mounted in the threshing and separation system, the helical geometryof the helical cutouts and helical mounting framework is generally inthe same direction, and parallel to a flow path of a spiraling cropflow. Rub bars are mounted to a surface of the grate and connected tothe mounting frames. The rub bars are mounted to the grate in a helicalfashion—meaning that the rub bars are mounted such that a length of eachof the rub bars is substantially perpendicular to the helical cutoutsand helical mounting framework.

According to another embodiment of the invention, a low cost and easymethod of manufacturing the helical bar concave is provided. Theimproved method of manufacturing a helical bar concave comprising: alaser cutting flat metal sheet to form a grate having a helical pattern,the helical pattern includes a plurality of helical mounting frameworkand helical cutouts in the grate; the cutouts in part forming a percentopen area in the concave having a helical geometry; cutting mountingholes in the mounting framework of the grate; rolling the flat, cut,metal grate to a predetermined radius; connecting the cut, rolled metalgrate to a box-shaped frame; connecting rub bars to an interior surfaceof the grate to form a functional surface for threshing a crop, the rubbars being mounted in a helical fashion meaning that the rub bars aremounted such that a length of each of the rub bars is substantiallyperpendicular to the helical cutouts and helical mounting framework.

In another aspect of the invention, the connecting of the rub bars tothe grate comprises a bolted configuration in which the rub bars may beeasily unbolted, moved to another location on the grate, and bolted inplace in the new location. The method allows for selectively configuringthe rub bars on the helical grate by mounting the configurable rub barsin a helical fashion to one or both of the interior surface and/or anexterior surface of the grate.

In another aspect of the invention, the rub bars are formed as segmentedrub bars. The segmented rub bars comprising straight pieces having alength that does not span the width of the box-shaped frame of theconcave, the segmented rub bars allowing the rub bars to be mounted to acurved surface of the grate in a helical fashion without bending ortwisting of the rub bar or grate.

Additional features and advantages of the invention will be madeapparent from the following detailed description of illustrativeembodiments that proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects of the present invention are bestunderstood from the following detailed description when read inconnection with the accompanying drawings. For the purpose ofillustrating the invention, there is shown in the drawings embodimentsthat are presently preferred, it being understood, however, that theinvention is not limited to the specific instrumentalities disclosed.Included in the drawings are the following Figures:

FIG. 1 is a perspective view of a combine harvester showing a partialcut-away in the area of the threshing and separating mechanism;

FIG. 2 is a detailed view of a helical bar concave that may be used inthe threshing and separating mechanism of FIG. 1;

FIG. 3 is a left side view of an exemplary rotor and concavearrangement; and

FIG. 4 is a top perspective view of the exemplary rotor and concavearrangement of FIG. 3.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The above problems in the prior art have motivated the creation of ahelical bar concave. Laser cut construction of the grate having helicalcutouts provides a low cost and easy to manufacture part. Segmented rubbars allow rub bars to be mounted in a helical fashion to asubstantially circumferential helical surface resulting in moreaggressive threshing. Bolted rub bar construction allows the concave tobe configurable. In preferred embodiments, the present invention isdirected to a concave having helically positioned segmented rub bars incombination with the helical nature of the grate cutouts and percentopen area geometry. The helical bar concave is particularly well suited,but in no way limited, for use with an axial flow combine and thehelical design and construction of the concave provides improvedthreshing and separation of spiraling crop materials being conveyedthrough the combine.

FIG. 1 shows an exemplary agricultural combine 10. As shown in FIG. 1,the combine 10 includes a longitudinally axially arranged threshing andseparation system 12, all of which, except for the improved helical barconcave 20 that is the subject of the present invention and which isincluded within the threshing and separation system 12, are of wellknown construction and operation. The helical bar concave 20 may also beused with combines having transversely aligned threshing and separationsystem in a combine.

As shown, threshing and separation system 12 is axially arranged, inthat it includes a cylindrical threshing rotor 14 conventionallysupported and rotatable in a predetermined direction about a rotationalaxis therethrough for conveying a flow of crop material in a helicalflow path through a threshing chamber 16 extend circumferentially aroundthe rotor 14. As shown, concaves 20 may extend circumferentially aroundthe rotor 14 and the flow of crop may pass in the space between thespinning rotor and the concaves. As the crop material flow through thethreshing and separation system 12, the crop material including, forexample, grain, straw, legumes, and the like, will be loosened andseparated from crop residue or waste such as, for example, husks, cobs,pods, and the like, and the separated materials may be carried away fromthe threshing and separation system 12 in a well known conventionalmanner.

FIG. 2 shows an exemplary helical bar concave 20. As shown in FIG. 2,the helical bar concave includes a frame 22 mounted to a grate 24. Asshown, the frame 22 includes side walls 26 and end walls 28 extendingbetween and connected to the two side walls 26. The side walls 26include a curved top edge 30 having a predetermined radius. The sidewalls 26 and end walls 28 define a top opening 32.

As shown in FIG. 2, the grate 24 includes a plurality of cutouts(openings) 34 and a plurality of rub bars 36. The grate 24 is connected(e.g., welded) over the top opening 32 in the frame 22. The grate 24includes an inside radius corresponding to the radius of the curved topedge 30 of the side walls 24. The radius is measured from thelongitudinal axis of rotation of the rotor and substantially correspondsto the curvature of an outer circumference of the rotor 14. The grate 24includes an interior surface 38 (also referred to inside surface or topsurface) and an exterior surface 40 (also referred to outside surface orbottom surface). The interior surface 38 comprising a concave functionalsurface for contacting a crop.

As shown, the cutouts 34 and rub bars 36 form a substantiallycircumferential helical surface. The helical nature of the cutoutsdefine a percent open area having a helical geometry. In the illustratedembodiment, balloon helical cutouts are provided although varying shapesand sizes for the cutouts are contemplated providing a general helicalconfiguration is included. The grate includes corresponding helicalmounting framework or mounting frames 42 in the concave's functionalsurface separating the cutouts 34. As shown, the grate 24 also includesholes 44 in the mounting framework 42 for mounting the rub bars 36 tothe grate 24.

The helical geometry or configuration of the mounting framework 42 isgenerally in the same direction, and parallel to the spiraling cropflow. Mounting framework 42 may be generally configurable at the time ofconstruction (e.g., at the time of laser cutting) and the mountingframework 42 may be of various sizes depending on the crop to beseparated. Mounting framework 42 and cutouts 34 may be used to set thehole spacing or govern the percent open area or free space in which thethreshed grain can fall through the concave.

Generally, the larger the crop or kernel being threshed, the larger thepercentage open area desired. For example, if a head of wheat beingthreshed is three inches long and the head is broken in half, you don'twant it to fall through because it is not fully threshed. What you wantto do is get all the kernels of wheat rubbed out of the head before itfalls through to the cleaning system. As such, mounting framework 42 andcutouts 34 may include various sizes depending on the concave product.

Mounting framework 42 and cutouts 34 on a concave may include astaggered mix of various sizes and/or shapes to effect and govern thepercent open area. The height of the mounting framework 42, which isessentially the material of a flat sheet of metal left after cutting thecutouts 34, is set below the height of the rub bars 36. For example, therub bars 36 may extend approximately an eighth to a quarter inch abovethe interior surface 38 of the concave 20.

The configurable rub bars are preferably formed as segmented rub bars.Segmented rub bars mean that the rub bars are formed as straight pieceshaving a length that does not extend all the way across the frameallowing the straight, segmented pieces to be mounted in a helicalfashion to the substantially circumferential helical surface of thegrate without bending or twisting of the rub bar or grate. Use ofsegmented rub bars also eliminates the need for additionally producingcomplex sheets that, for example, have twists or helical forms to them,and also allows the segmented rub bars to be reversible front to back.

As shown in FIG. 2, the concave 20 includes configurable rub bars 36. Asshown, rub bars 36 may be mounted (e.g., bolted) to the interior surface38 of the concave 20 in a helical fashion to create a rub surface on thesmooth inner radius of the concave 20 to provide more aggressiveseparation of crop passing thereover. Mounting the configurable rub bars36 in a helical fashion means that the rub bars 36 are mounted such thatthe length of the rub bar 36 is substantially perpendicular to thehelical cutouts 34 and mounting framework 42 (and substantiallyperpendicular to the spiraling and helical crop flow).

Embodiments of the present invention having configurable rub barsinclude removable rub bars. For example, a bolted configuration allowsthe rub bars to be removed and reconfigured on the grate for aparticular use or crop.

Although it is preferred in certain embodiments that the rub bars bemounted perpendicular or substantially perpendicular to the crop flow,other embodiments contemplate that the rub bars may be mounted at anangle to the crop flow. For example, in some embodiments, the rub barsmay be mounted at an angle of about 85 degrees to about 95 degrees tothe direction of crop flow. For example, in other embodiment, the rubbars may be mounted at an angle of about 80 degrees to about 100 degreesto the direction of crop flow. This may result, for example, from theneed for adjustments in the speed of the rotor and crop flow through thethreshing chamber based on crop type, crop condition, etc., resulting insome angle of incident of the crop hitting the rub bar surrounding 90degrees. Generally, the closer to perpendicular the rub bars are to cropflow, the more aggressive the threshing.

Alternatively, the rub bars 36 may be mounted (e.g., bolted) to theexterior surface 40 (i.e., on the box side) to cover up cutouts 34 inorder to: provide a smoother surface in the interior surface and/orreduce the percent open area by blocking off separation of the rear ofthe concave. In another embodiment, the configurable rub bars 36 may bemounted to either of the inside and outside surface(s) 38, 40. In yetanother embodiment, the configurable rub bars 36 may be mounted to bothof the inside and outside surface(s) 38, 40.

Use of a bolted configuration in the mounting of the rub bars 36 to themounting framework 42 of the grate 24 allows the rub bars 36 to bereplaceable (e.g., to replace worn or damaged rub bars 36; to change thetype/style of rub bar 36 based, for example, on the crop, etc.). Also,use of a bolted configuration in the mounting of the rub bars 36 to themounting framework 42 of the grate 24 allows the rub bars to beinterchangeable (e.g., on a particular location on a surface 38 or 40 ofthe grate 24 or between surfaces 38 and 40 of the grate 24). Inaddition, use of a bolted configuration in the mounting of the rub bars36 to the mounting framework 42 of the grate 24 allows the rub bars 36to be scalable (e.g., the number of rub bars 36 may be increased ordecreased).

The segmented and configurable rub bars allow a plethora of options andconfigurations for mounting the rub bars to the grate. For example, therub bars may be mounted in series on the same side of the grate; mountedback to back (i.e., one on the inside surface and another on the outsidesurface; mounted in series but alternating front to back; mounted in apattern on one or both sides of the grate; mounted randomly on one orboth sides of the grate; etc. Where rub bars overlap top to bottom, thesingle bolt may be used to secure an end of two separate rub bars.

In a preferred embodiment, the rub bars 36 comprise U-shaped rub bars.When mounted to the inside surface 38 of the grate 24, the U is facingup, towards the threshing surface of the rotor 12, so that as the cropprogresses across the U-shaped rub bar two upset edges 46 areencountered. In the embodiment having the U-shaped rub bars 36 mountedto the exterior surface 40, the rub bar 36 is flipped so that the U isfacing outward, away from the rotor 12 and threshing surface, so thatcrop does not get caught in the channel 48 of the U-shape member. Therub bars may include various shapes. For example, the rub bars maycomprise rectangular shaped bars, L-shaped bars, rounded bars, etc. Therub bars may include various shapes and sizes. For example, the rub barsmay have a length that span one mounting frame, two mounting frames,threes mounting frames, etc.

FIGS. 3 and 4 show an exemplary rotor 12 and concave 20 arrangement. Asshown, the concaves 20 may be mounting in close proximity to the rotor12 with a space or clearance therebetween for a crop to flow. In atypical combine 10, an individual concave 20 may wrap approximately 150to 160 degrees around the rotor 12. The concave 20 may comprise onepiece or may be split into multiple parts. For example, the concave maybe split into two halves that may be connected together end-to-end toform a full concave. End walls 26 may include one or more openings orholes 27 for receiving a fastener (e.g., a bolt) for connecting the twohalves of the concave together (see e.g., FIG. 2). This feature may beadvantageous, for example, on larger combines to facilitate handling,installation and removal.

Further, H-frames may be provided for mounting of the concave orconcaves. In the embodiment illustrated in FIGS. 3 and 4, two H-frameboxes may be provided having four module positions or mounting locationsfor receiving individual concaves. A complete combine may include, forexample, four left concaves and four right concaves to produce a fullyoff-setted threshing module.

The concaves may be configurable and interchangeable between positionsto allow the combine to work with a variety of threshable crops. Theconcave modules may be selected and positioned to thresh and separategrain appropriately at a relatively high capacity. For example, theconcave in the number 1 position and the number 4 position may beinterchangeable and the concaves in the number 2 position and the number3 position may be interchangeable. Typically, concaves on the right sidemay be interchangeable with one another (switching position front toback) and concaves on the left side may be interchangeable with oneanother (switching position front to back). Typically, concaves from theleft side may not be exchanged with concaves on the right side due tomounting configurations.

As shown in FIGS. 3 and 4, the front concaves may have a small mountingframe configuration and the back concaves have a larger mounting frameconfiguration—i.e., more percent open area. Although the concaves shownin FIGS. 3 and 4 show conventional concaves—i.e., having straight wiresthat are parallel to the frame sidewalls and rub bars that areperpendicular to the frame sidewalls and hence do not have a helicalconfiguration, those skilled in the art will appreciate that the helicalbar concave of the present invention (e.g., as shown and described abovewith reference to FIG. 2) may be mounted in a similar fashion as shownand in place of the illustrated concaves.

FIGS. 3 and 4 show a left side view and a top side view, respectively,of an exemplary rotor 12. As shown, the rotor 12 rotates clockwise whenviewed from a position at the rear of the rotor, looking forward to thedirection of travel (arrow 50). That is, the illustrated rotor 12 ofFIG. 3 is rotating such that the top of the rotor is going into the pageand the bottom of the rotor would be coming out of the page.

As shown, the rotor 12 includes a front rotor support 52 at the front(the left side in the figure). The illustrated support includes a frontrotor support 52 having a C-channel curvature that holds up and supportsthe rotor 12. The in-feed area 54 of the rotor is from that bearingsupport plate or that rotor support channel to the number one moduleposition which is mainly constructed of the conical grey cone 56 and thehelical auger plates 58.

After this transition area 54, the crop goes through an accelerationperiod in which you have a feed device that is feeding crop from theheader. The crop is fed at some factor of acceleration, which maydepend, for example, on how fast the rotor is spinning and how fast thefeeder is going, etc. But generally, there is always an increase inspeed of the crop in this regions of the combine. The motion of therotor 12 also acts to thin the crop and transmits it rearward. The rotorconveys the crop into the thresher section 60 of the rotor, which is thetubular portion. Rasp bars 62 are mounted using conventional techniques(e.g., bolted) to the barnacles or the rasp bar supports 64. The raspbar supports 64 may be connected using conventional techniques (e.g.,welded) to the cylindrical portion of the rotor 12.

In the illustrated rotor arrangement, primarily positions number one andtwo (also referred to as module positions number one and two) may beadjustable and these modules set the threshing clearance (the distancebetween the rotor (and rotor rasp bars) and the concave (and concave rubbars)). For example, if you are threshing wheat, one would like totighten up the clearance due to the small kernel size. For corn, youwould want a more open area similar to the height of a cob, and theadjustable feature allows an operator to tailor and adjust for threshingbased on the particular crop. This position is where the grinding andthreshing action occurs and where most of the grain is threshed.

Positions 3 and 4 may be a fixed arrangement, although these positionsare not limited to a fixed arrangement. The area in the number 3 andnumber 4 module positions are typically called the separation area.Typically, a wider clearance is run in the separation area as comparedto the threshing area since by this time the crop is substantiallythreshed. In the separation area the main objective is simply trying toallow more open area to allow the loose, free grain to escape from thestraw and fall through the cutouts or open area of the modules.

The first and second module positions typically have tighter clearancesand less percent open area as compared to the third and fourth modulepositions. The actual clearance for each module position may bedetermined and set to achieve the desired grind or rub the cropadequately to thresh the grain. This customization and adjustability maybe determined based on a number of factors, such as the crop, plantcharacteristics, the growing seasons, and the like. For example,sometimes it is desirable to run a very wide clearance for wheat,sometimes it is required to run a very tight clearance for hard tothresher wheat.

As shown, a helical kicker 66 may be provided at the rear of the rotor(right side in the figure) to expel the crop out of the threshingchamber. Typically, this expelled material goes either onto the groundor into a collection device, such as a straw chopper or a dischargebeater, in which a subsequent action may be taken on the straw. As thecrop flows through the threshing chamber, it flows in a cylindrical orspiral pattern as a result of the rotating rotor. When it gets to therear of the rotor, that rotor ends and so does the crop flow path. Thehelical kicker 66 helps ensure full discharge of the crop from thethreshing chamber.

Embodiments of the present invention also include improved methods ofmanufacturing a helical bar concave. The method of manufacture includeslaser cutting flat metal sheet to form a grate having a helical pattern.The helical pattern includes a plurality of helical mounting frames andhelical cutouts in the grate. The cutouts in part forming a percent openarea in the concave having a helical geometry. Mounting holes areprovided in the grate for mounting (e.g., bolting on) of configurablerub bars. The flat, cut, metal piece may then be rolled to apredetermined radius. The rolled, cut, metal sheet may then be connected(e.g., welded) to a box-shaped frame to form a configurable helicalgrate. Selectively configuring the configurable helical grate bymounting the configurable rub bars in a helical fashion to one or bothof the interior surface and/or the exterior surface of the grateprovides improved performance and flexibility in operations.

The combination of laser cutting a grate having helical shape orgeometry in combination with configurable rub bars creates aconfigurable rub surface and a means to: change the aggressiveness ofthe functional surface of the grate; and/or change the percent open areaby reversing the rub bars and mounting them on the back side of thegrate to close off one or more cutouts.

In one embodiment, the helical bar concave may be used in applicationshaving requirements to collect an additional quantity of larger cropmaterials, such as, for example, corn cobs. In order to achieve thisobjective, it is desirable to have more open area within the concavemodule. The design and construction of embodiments of the presentinvention allow efficient threshing and separation of larger cropmaterials by providing a helical bar concave having a substantiallygreater open area.

At the same time, embodiments of the present invention are configurableand scalable in that the bolted bar design and construction allows oneto adjust the number and position of the rub bars thereby easilychanging the concave's configuration and threshing/separatingcharacteristics. For example, more or less open area may be providedsimply by changing the number, orientation, or location of the rub bars.In addition to changing the number and/or location of the rub bars, theclearance between the balloon helical cutouts in the concave grate maybe used to set the percent open area. For example, more or less openarea may be provided simply by changing the amount of laser cutting fromthe part.

The number, orientation, and location of the rub bars, as well as thepercent open area in the grate may be determined based upon a functionalobjective of a particular user. For example, this determination may bebased on factors such as, for example, crop type, nature of the crop,plant maturity, moisture content, weather conditions, what you want toallow to pass through the concave module (e.g., free grain, grain andsome waste, etc.), etc. The objective may include a feed product, agrain product, and the like. As way of example, wheat and other smallgrains will typically have relatively small crop residue components thatrequire a smaller percent open area, whereas other grains, such as corn,will typically have larger components, such as thick stalk segments, cobfragments, and large leaves that dictate a larger percent open area inthe concave grate.

Part of the motivation for the present invention comes from wanting tobe able to separate even the larger pieces of material by achieving evenlarger percent open areas in the concaves. In one embodiment, this maybe achieved by forming longer unobstructed openings. For example, largerpercent open areas in the concaves may provide advantages for separatingpieces of cob (e.g., 1-inch diameter and 2-3-inch length) along withsome of the kernel or grain (e.g., ¼-inch-⅜-inch generally square shapewith ⅛-inch thickness). Larger percentage open areas may be achieved,for example, by making larger laser cuts and/or unbolting and removal ofbolted-on rub bars. The removable design of the rub bars allowstailoring of the size of the separation area. Embodiments of the presentinvention provide the ability to create a significant amount of openarea with a very low cost construction. The present invention may bemanufactured by laser cutting and rolling a flat sheet of metal, therebyreducing/eliminating the need to laser cut and then weld each pieceresulting in reduced steps and costs. Another motivating factor for thepresent invention was the desire to create improved threshing andseparation in a helical fashion. Yet another motivation for the presentinvention was the desire to create a bumpy ride for the crop as ittravels over the concave and the rub bars to cause agitation and rubbingof the crop resulting in improved separation of the grain from the wastematerial. Embodiments of the helical bar concave and method ofmanufacturing same satisfy the above needs, as well as other needs.

Although the invention has been described with reference to exemplaryembodiments, it is not limited thereto. Those skilled in the art willappreciate that numerous changes and modifications may be made to thepreferred embodiments of the invention and that such changes andmodifications may be made without departing from the true spirit of theinvention. It is therefore intended that the appended claims beconstrued to cover all such equivalent variations as fall within thetrue spirit and scope of the invention.

What is claimed:
 1. An improved method of manufacturing a helical barconcave, the method comprising: laser cutting flat metal sheet to form agrate having a helical pattern, the helical pattern includes a pluralityof helical mounting framework and elongate helical cutouts extendingsubstantially the length of the inside radius in the grate; the elongatehelical cutouts in part forming a percent open area in the concave, thecutouts arranged in a helical geometry to form a substantiallycircumferential helical functional surface; cutting mounting holes inthe mounting framework of the grate; rolling the flat, cut, metal grateto a predetermined radius; connecting the cut, rolled metal grate to abox-shaped frame; connecting rub bars to the interior functional surfaceof the grate for threshing a crop, the rub bars being mounted in ahelical fashion meaning that the rub bars are mounted such that a lengthof each of the rub bars is substantially perpendicular to the helicalcutouts and helical mounting framework.
 2. The method of claim 1,wherein the connecting of the rub bars to the grate comprises a boltedconfiguration in which the rub bars may be easily unbolted, moved toanother location on the grate, and bolted in place in the new location.3. The method of claim 2, further comprising selectively configuring therub bars on the helical grate by mounting the configurable rub bars in ahelical fashion to one or both of the interior functional surface and/oran exterior functional surface of the grate.
 4. The method of claim 2,further comprising forming the rub bars as segmented rub bars, thesegmented rub bars comprising straight pieces having a length that doesnot span the width of the box-shaped frame of the concave, the segmentedrub bars allowing the rub bars to be mounted to a curved surface of thegrate in a helical fashion without bending or twisting of the rub bar orgrate.